In a cohort study, investigators found that respiratory tract infections early in life are associated with development of atopic dermatitis in childhood.
Previous studies on the relationship between early respiratory tract infections and atopic dermatitis have been unclear, with inconsistent findings. This study, conducted by Niklas Brustad, MD, PhD, from the University of Copenhagen, in Copenhagen, Denmark, and colleagues aimed to further evaluate this potential link between early infection burden and infection subtypes and the risk for childhood atopic dermatitis.
The investigators used the 2010 Danish Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010) to obtain data on 663 children aged 0 to 10 years. The data included diagnoses of infection and atopic dermatitis, Scoring Atopic Dermatitis (SCORAD) index score, exposure to systemic antibiotics, and FLG status. For the purpose of replication, they obtained data on a second cohort of children within the same age range from the US Vitamin D Antenatal Asthma Reduction Trial (VDAART). In the VDAART cohort, parents reported a diagnosis of atopic dermatitis by a physician until children reached the age of 6 years. In both cohorts, episodes of infection were recorded in daily diaries until children reached the age of 3 years. In the COPSAC2010 cohort, episodes of cold, acute otitis media, tonsillitis, pneumonia, gastroenteritis, and fever were recorded. In the VDAART cohort, episodes of cold, fever, respiratory tract infection, and fever were recorded. The outcomes were risk for atopic dermatitis from birth 0 to age 10 years; analyses were adjusted for FLG variant and systemic antibiotic treatment.
In COPSAC2010, children in the upper tertiles of infection episodes and days, had a higher risk for yearly prevalence of atopic dermatitis from birth to age 10 years (adjusted odds ratio [AOR], 1.91; P=0.03) when compared with children in the lower tertiles (AOR, 1.69; P=0.01). Each episode of infection was associated with a higher risk for atopic dermatitis, independent of systemic antibiotic treatments and FLG variant. Associations between infection and atopic dermatitis were mainly driven by respiratory tract infections.
In VDAART, children in the upper tertiles of infection episodes and days, had higher risk for atopic dermatitis from birth to age 6 years when compared with children in the lower tertiles (OR, 1.76; P=0.01). The association again increased with each infection episode.
Dr. Brustad and colleagues concluded that the “results of this study suggest that early-childhood respiratory infection burden is associated with a higher risk of AD [atopic dermatitis] in a dose-dependent manner.”